China Inspection and Quarantine Inspection, Factory Inspection, Certification and Testing [Inspector Encyclopedia] Flat-Panel TV and Set-Top Box Energy Efficiency Inspection and Testing

GB 24850-2020, "Limited Values ​​and Energy Efficiency Grades for Flat-Panel Televisions and Set-Top Boxes," is a mandatory national standard that specifies energy efficiency requirements, test methods, and compliance criteria for these products. This standard serves as the core basis for product inspection, factory audits, and third-party quality testing, and is applicable to product quality audits, factory inspections, and market supervision spot checks.

1. Scope and Applicability of Inspection

This standard applies to liquid crystal televisions (LCD TVs) and organic light-emitting diode televisions (OLED TVs) whose primary function is to receive, demodulate, and display signals, operating under AC 220V, 50Hz power supply conditions. This standard also includes display devices that lack tuners but are marketed as television products. It also covers all types of set-top boxes (cable, terrestrial, satellite, and internet-based) operating under normal operating conditions.

During the inspection process, it is necessary to first confirm whether the product's scope of application meets the requirements of this standard. During the factory inspection, it is necessary to verify whether the factory has implemented this energy efficiency standard in product design, raw material procurement and production.

2. Definition of terms and their association with inspection

• On mode : The state in which the product is connected to a power source and performing its primary functions. Power and energy efficiency indicators should be measured in this state during inspection.

• Passive standby mode : A state in which the device is connected to a power source but not performing its primary functions. During inspection, power consumption in this state must be specifically tested to determine whether it exceeds the specified limits.

• Minimum allowable values ​​of energy efficiency : These are the minimum energy efficiency values ​​permitted for a product and are mandatory requirements. Failure to meet these values ​​during inspection will be considered a major defect and the entire batch will be rejected.

3. Energy efficiency rating and inspection judgment

1. Flat-panel TV energy efficiency ratings

It is divided into 5 levels, with level 1 being the highest. When inspecting the product, the energy efficiency level to be met should be determined based on the screen resolution:

• Resolution ≤ 1920×1080: should be no less than level 3;

• 1920×1080 < resolution ≤ 3840×2160: should be no less than level 4;

• Resolution > 3840×2160: should be no less than level 5.

During inspection, use a power meter and luminance meter of appropriate accuracy to measure and calculate energy efficiency values ​​according to standard requirements, rounding the results to two significant figures. Factory inspections should also examine whether the factory has qualified testing equipment and regular calibration records.

2. Set-top box energy efficiency rating

There are three levels, with Level 1 being the highest. Inspection requires testing operating power and passive standby power, and confirming how the power consumption factor (ΣPf𝑎) for each additional function is accounted for. The results should not exceed the Level 3 limits in Table 2.

IV. Energy efficiency limit values ​​and inspection qualification bottom line

• The energy efficiency limit values ​​for flat-screen TVs and set-top boxes are both level 3. Products below this requirement are considered unqualified.

• The inspection sampling plan can be implemented according to the AQL plan, but energy efficiency is a key characteristic and the "zero tolerance" principle is usually implemented. If one unqualified case is found, the entire batch may be returned.

• During the factory inspection, the focus should be on whether the factory has established an energy efficiency self-inspection process and retained test records and a log for handling non-conforming products.

V. Energy efficiency test methods and inspection implementation requirements

1. Flat-panel TV testing process (key inspection steps):

a. Equipment connection : Connect the test system according to the standard drawings. The brightness test distance is 3 times the screen height. If the device has multiple modules with independent power supply, all modules need to be connected to the power meter for overall measurement;
b. Preheating : Input standard dynamic video signal, preheating ≥ 30 minutes;
c. Adjust to standard state : Set the standard image mode (such as standard/movie mode) and turn off all energy-saving and light-sensing functions;
d. Brightness test : Use a calibrated luminance meter to measure the brightness of points P0 to P8 and calculate the average brightness;
e. Power test : Measure the startup power P𝑘, calculate the energy efficiency value, and determine whether it meets the corresponding level.

Test environment requirements: temperature 23±2℃, humidity 45%~75%, avoid direct sunlight, and stable grid voltage.

2. Set-top box testing process (key inspection steps):

a. Wiring confirmation : Connect according to the standard diagram based on the type of set-top box (cable/satellite/network), and preheat for more than 5 minutes;
b. Preheating : Input the activity sequence signal, preheating ≥ 15 minutes;
c. Working power test : Use a digital integrating power meter to test for ≥10 minutes and calculate the average value;
d. Standby power test : Enter passive standby, wait for 5 minutes, and test the lowest power value;
e. Record and determine : If there are multiple standby modes, take the one with the lowest power as the result.

During the factory inspection, it should be checked whether the factory testing environment meets the standards, whether the instruments are within the valid calibration period, and whether the operators have been trained.

6. Key points of factory inspection

1. Document Review :

   • Whether the latest version of the standard is available;

   • Whether energy efficiency control procedures and operating instructions have been established;

   • Check whether the calibration certificate of the testing equipment is valid;

   • Past energy efficiency test records and non-conforming handling reports.

2. On-site audit :

   • Check whether the environment meets the standard requirements;

   • Whether the operator performs the test according to the standard;

   • Whether energy efficiency items are included in incoming material inspection (IQC) and finished product inspection (OQC);

   • Whether energy efficiency verification has been performed on key components (such as power modules and LED backlights).

3. Sampling retest :
   Auditors should take samples from the finished product warehouse and conduct independent energy efficiency tests to verify the consistency of the factory test results.

VII. Common inspection failures and treatment suggestions

• If the energy efficiency value is lower than the limit : immediately suspend inspection and find the cause (such as power supply solution change, software configuration error, use of non-standard components);

• Excessive standby power : This is common in set-top boxes and requires checking the power management circuit and software version;

• The test environment is not suitable : such as the luminance meter is not calibrated, the test distance is wrong, the voltage is unstable - the test should be repeated;

• Documents do not match the actual product : If the energy efficiency rating indicated on the product is inconsistent with the actual test results, it is a serious fraud and must be reported to the market supervision department.